Extensible propeller



Filed March 154 1922 y 3 Sheets-Sheet 1 April 29, 1924. 1,491,972

M. SCHIESARI EXTENSIBLE PROPELLER Filed March 13. 1922 3 Sheets-Sheet v231A/vez -L f om April 29 1924. 1,491,972

M. SCHIESARI EXTENS IBLE PROPELLER Filed March 13, 1922 3 sheets-sheet sl Patented pr. 29, 1924.. y y

UNITED STATES PATENT OFFICE.

Application led March 13, 19,22. Serial No. 543,303.

To all whom t may con'cerm,

Be it known that I, MARIO ScHmsARr, a citizen of the United States,residing at New York, in the county and State of New York, have inventedcertain new and useful Improvements in Extensible Propellers, of which`the following is a full, clear, and exact description, reference beinghad to the accompanying drawings, forming part of this specification.

This invention relates to extensible propellers consisting of aplurality of inclined planes or blades connected to an axle and to eachother by flexible retaining means, and rendered operative through theutilization of centrifugal force, of the type described by me in anotherapplication for patent led by me July 14, 1921, having for title Methodand apparatus for aerial propulsion, Serial No. 484,827; and its mainobject is to provide a novel method of construction of extensiblepropeller, whereby the variations of its radius of action are utilizedto modify the angle of incidence of its planes, so as to substantiallycounterbalance the variations in the torque of its axle due to Saidvariations in its radius.

A further object of my invention is to provide a propeller of a noveland improved design, the action of which is based on utilizing thelifting or propelling force obtained through causing inclinedlplanes 0rblades connected to an axle and to each other by flexible retainingmeans, to travel in a circular path at a suitable speed; said propellerhaving a variable radius of action, and also being provided with meanswhereby the angle of incidence of the planes to their plane of travelmay be varied, in order to realize certain advantages in operation, as

y will hereafter be more fully explained.

Astill further object is to provide, in a propeller consisting of aplurality of planes or blades connected to an axle and to each other byiexi'ble retaining means, means whereby the planes or blades may becaused to assume different angles of incidence to `their plane oftravel.

With these and other objects in view, as will more fully appear as thedescription proceeds, my invention furthermore consists 1n certain novelconstructions and arrangements of parts as will be hereinafter fullydescribed and claimed in the appended claims.l

In my other patent application above referred to, the advantages of thistype of propeller have been fully set forth; the same beingsubstantially an adaptation of aerofoil elements in combination with arotating axle, the lifting or propelling power developed by saidaerofoils set at a certain anglel of incidence to their plane of travelbeing made available through a novel method of exploitation ofcentrifugal force. In order to attain greater efficiency in a propeller,it is desirable to make the same of a large diameter, and low angle ofincidence; but

with Apropellers of ordinary design there' are sharp limitations imposedby practice in determining these factors of construction.

ditions for the engine. -The improve propeller formin the object of myother patent application a ove referred to, permits of realizing theseadvantages, on account of its diameter being variable and under thecontrol of the operator; and if the engine is operated at a uniformspeed, as the diameter of the propeller is increased, so is its pullproportionately increased, with slight variations in efficiency due tochanged conditions.

With this type of propeller, however, it is obvious that the angle ofincidence of the planes or blades must be such as to exert a sufficientpull even when the diameter of the propeller lis small; with the resultthat when the diameter is increased it may be necessary to cut down thespeed of the engine in order to avoid considerable overloads. The torqueon the axle however, will increase with the increasing of the diameterof the propeller, and is not affected by variations in speed; and thiscondition therefore constitutes in practice a serious limitation to thediameters attainable, and to reductions in the size of the axle.

In order to realize conditions whereby the engine may be run at asubstantially uniform speed, and the torque exerted on the axlemaintained within reasonable limits, I have sought to modify another oneof the factors concurring in the determination of these conditions, viz,the angle of incidence of the lanes to their plane of travel; since byecreasing the said angle of incidence as the diameter of the propellerincreases, not only is the pull considered in relation to thecircumferential speed decreased, but a higher efficiency' for the de'-vice as a whole is attained.

I have therefore devised a novel and improved construction of extensiblepropeller having a variable angle of incidence of its planes or blades,said angle decreasing as the diameter of the propeller is causedtoincrease, and vice versa the radial travel of the planes or bladesthemselves being used in order to cause corresponding variations intheir angle of incidence. y

For purposes of illustration, in the drawings I show one of the ways ofcarrying m invention into practice, and a few apphcations,

of propeller as a whole. Referring to t e same:

Figs. 1 and 2 are diagrammatic views of the composition of centrifugaland lifting forces taking place in the operation of my propeller; v

Fig. 3 1s a plan Vview of one of the aerofoil type planes entering intothe construction of my propeller;

Fig. 4 1s a cross sectional view in elevation of the same;

Fig. 5 is a cross-sectional view in elevation of thesame, tilted at adifferent angle of incidence to the plane of travel;

Fig. 6 is a view in perspective of a complete propeller in a retractedposition;

Fig. 7 is a detail plan view of one of the sheaves controlling theoperation of the planes;

Fig. 8 is a detail cross sectional view in elevation of the same;

Fi 9 is a detail plan sectional view showmga modified type of sheave andcable;

Fig. 10 is a view in perspective of an aeroplane fitted with my improvedpropeller;

Fig. 11 is a view in perspective of a flying machine of the helicoptertype fitted with two propellers rotating in opposite directions;

Fig. 12 is a cross sectional view in elevation of an aeroplaneillustrating one.

of the ways of controlling the operation. of my propeller; A

Fig. 13 is a detail plan sectional view of same through line A--A ofFig. 1 2; and

Fig. 14 is a plan sectional view of the same through line B-B of Fig.12.

In order to facilitate a thorough understanding of the presentinvention, in Figs. land 2 I show in a diagrammatic form the compositionof forces governing the opwith and, for the sake of clarity, also -thegeneral mode of operation of my ty e eration of my improved propeller.Let us assume that the flexible member B carrying a weight at P, be..revolvin at such an angular velocity about the xed point B as todevelop at P a centrifugal force C. Evidently, if the force C was theonly force acting on the system, the member B P could not be inequilibrium. If we apply at P another force f of such a magnitude thatthe resultant R, obtained by compounding it with C, will be in alinementB P, the moment of said resultant about the fixed point B will be zero,and the system will consequently be in equilibrium.

Considering the moments of the component forces about B we find.

cm=fn (1) j' 'fm (2) P, 1n clined at an angle a to the vertical andltherefore the flexible member B P will be only slightly inclinedupwardly in respect to the horizontal. Y

In Fig. 2, I show how two lifting (aerofoils) forces actingsimultaneously will compound themselves in a double lifting forceaxially directed.

In Figs. 3, 4, 7 and 8, I show'an aeroform design of propeller plane,which must be properly built with suitable materials in strength. In thesame, 1 designates the plane, proper, titions 2. 3, 4, designate theretaining ca each forming a closed circuit between two adjacent Thenumber of cables used is equal to the number of planes entering into theconstruction of the propeller, so that in the propeller shown in Fig.,10, comprising three planes, three cables 5,` 6, 7, are employed, whilein the propeller the hub of which is shown in Fig. 14, comprisingfourplanes, four cables 8-8, 9-9, 10-10',and 11- l1 areemployed.

` In said Fig. 14, it is seen thatV all the cables are inserted through,and retained by the hub 12, the two strands of each cable.thus obtainedbeing wound spirally around said hub in a flat spiral; so that if thehub is rotated in the direction of the arrow all the cables aresimultaneously unwound of the same quantity, while the reversev happensif the hub is rotated ,in the reinforced by aluminum arles,

planes and the hub, as will be l clearly seenV by referring to Figs. 10,14.l

105 order to secure the necessary hghtness and opposite direction. Meansfor controlling the operation of the hub for winding or unwinding willbe described later; but assuming that the relative position of thecables and the hub be rendered stationary it will be seen that if thepropeller thus formed is rotated at considerable speed the effect of thecentrifugal force exerted on the planes will be to keep the same undertension both radial] and peripherically. iIn order to create 1n theplane elements a tendency to axial movement however, it is necessary ltomaintain the active surfaces of said planes at an angle of incidence inrelation to the plane of rotation; and this is obtained by making guidemembers 13, 14 for the cables, with a bent portion 15, 16 suliicientlylong, and bent at the right `angle so as to maintain the periphericalstrands of the cables in the right position. In other words, therearward bent port-ion 15 of one plane must be directed towards theforward bent portion 16 of the adjacent plane.

The action of the air against the plane surfaces will be the same forall the planes of a propeller, and will constantly create a tendency inthe rear part of a plane and the front part of the adjacent plane tomove away from each other. This will obviously be prevented by theperipherical strand connecting said two portions of adjacent planes. andtherefore the angle of incidence will be maintained throughout. For eachplane we have, therefore, ycreated the condition diagrammaticallyillustratedv in Fig. 1. C representing the centrifugal force tending tocause the planes to move in a radial direction and F representing thereaction of the air striking the inclined ysurfaces of the planes andcausing the same to move in an axial direction, the resultant force Rhaving the effect of maintaining th'e retaining cables under tension atan upwardly inclined angle. A propeller being formed of a plurality ofsymmetrically arranged elements, counter-balancing each other, a systemwill have been created such as diagrammatically illustrated in Fig. 2where the ultimate resultant force is axially directed, same as in apropeller ofordinary construction.

The general mode of operation of the propeller forming thc object of thepresent invention, is therefore essentially the same asin the case ofthe propeller described and claimed in my previous patent applicationabove referred to; with the difference that in the present instance Ihave provided means whereby the angle of incidence' of the planes may bevaried, andv will automatically become smaller as the diameter of thepropeller increases.

As explained above, through this improvement an equalizing effect willbe obtained on the torque of the axle on which the prouse propellerswith a larger diameter and smaller angular speed, realizing a bettereiciency for the propeller and better working conditions for the engine.

The operation o f my device is based on the fact that as the propellerexpands, the strands of cable connecting adjacent planes become longer;and therefore an outward movement of said cables relative to said planesmust take place. Instead of causing the relative position of the planesand the cables passing therethrough permanently set at a given angle,therefore, I cause the said relative position to change from a highangle to a low angle as the diameter of the propeller is graduallyincreased. To this end, I provide the planes with adjustable guidingmeans for the cable strands, the relative position of which to theplanes is adapted to change as ythe strands arecaused to travel in oneor the other direction; and these relative movements being such thatwhen the rear portion of a plane is moved upwardly so as to diminish itsangle of incidence, its front portion is moved downwardly, so as toachieve the same effect; so that the cumulative effect on the plane willbe a tilting movement of the same around an imaginary intermediatelongitudinal axis. This movement will take lace so as to diminish t-heangle of inci ence as the propeller is expanded, and in the oppositesense as the propeller is contracted.

This action of the propeller planes may easily be conceived, byimagining the path of travel of the cables to be permanently set on aplane normal to the axis of the propeller, and by imagining a gradualchange in the an le between said plane and the surfaces of -t epropeller planes.

In the drawings I show one of the ways of carrying my invention intopractice, and in the same, Figs. 3, 4, 7, 8, it is seen that for eachstrand of cable 3, 4, I provide in the plane a set of two guidingsheaves 17, 18, 17 18, mounted on screws 19, 20, 19', 20', and adaptedtherefore to axially travel thereon as said sheaves are being rotated. f

Referring to Fig. 3 it is seen that when both strands travel outwardly,sheaves 17 18 are caused to rotate clockwise, and sheaves 17, 18, arecaused to rotate in the opposite direction. All the screws being with aright hand thread it follows, by referring to Fig. 1, that sheaves 17',18 will travell downwardly on their screws, and sheaves 17, 18 will moveupwardly, so that the plane will gradually come to assume the positionshown in Fig. 4 where the angle of incidence to the plane of travel C C,has become less. The reverse will obviously take place when thepropeller is contracted, and the cables will travel inwardly instead ofoutwardly.

During their travel, the sheaves will carry can be predetermined bymeans from those adopted.

guide members 13, 14, which are also inserted on the screws, and whichare provided, as hereinbefore stated, with bent portions 15, 16. Inorder to assure an intimate contact between the cables and the sheaves,I prefer to increase the a le of contact between them by means of idlerollers 22, 23. The contact between cables and sheaves however, ispurely frictional, and if a more positive relation of movements betweenthese factors should be necessary, a modification on the order of theone shown in Fig. 9 `may be the cable 24 is shown IprovidedwithemuidistantA rings 25, causing the same to act ike a, chain in meshwith sheave 26, the groove of which is provided with notches l27. Thedriving action will thus be absolutely sitive, and all danger of lostmotion throng slippage eliminated.

It is obvious that all parts can be so proportioned, and the thread ofthe screws so cut that the gradual change in the angle of incidence ofthe planes will take place between a maximum and a minimum which thedesigner. Similarly, the screws of one set may have a different pitchfrom those of the other set, or the sheaves may have dilerent diameter,so that if desired the axial travel of one set of sh'eaves may bedifferent from the one of the other set. Also it is obvious thatdifferent shown may be used in order to change the angle of incidence ofthe planes by utilizing the travel of the cables, the device describedbeing mainly for purposes of illustration.

My propeller may be used singly, as shown in the aeroplane in Fig. 10,or may be used in connectlon with another turning In the same in anopposite direction in order to pre-` vent spinning of the machine aboutits axis in flying machines ofthe helicopter type,

such as shown 1n Fig. 11. The manner of control of the expansion andretraction of the propeller does not form a part of the resentinvention; but for the sake of clar- 1ty, and in order to assist inunderstanding its operation, in Figs. 12, 13, 14 I have illustrated, andI will here describe, a mechanism which may be used for the control of apropeller of the single type.

In the same, frame motor integral with an axle 102 which is formed witha tapered portion 103.

On said axle is inserted a sleeve 104 mounted on they horizontal shaft122 pivotally mounted on an aeroplane body or fuselage 126.

122 by means of lugs 121-121. Said shaft 122 may be rotated around itsaxis by means of a worm wheel 123 operated by worm 123', which iscontrolled by a hand wheel 124, so that axle 102 may be caused to assumea motion on said axle so that 101 designates a rotatable 120 designatesa frame in` which the motor is mounted fixed on shaft two collar membershorizontal position toward the front of the machine.

On axle 102 is also mounted another sleeve 105 having a tapering portionsupported by the tapered portion 103 of axle 102 and becoming integraltherewith on account of the wedging action taking place; said sleeve 105however, is capable of axial it may be detached from close contact withtapered portion 103 and rendered loose on said axle. The upper partofsaid sleeve is formed with teeth 117, 118, constantly in mesh withsimilar teeth provided on the lower face of a core 116 to which arefixed' the flexible elements as shown in Fig. 14, and which is .looselymounted near the end of axle 102.

Said core 116 is locked against axial motion by two blades or flanges106, 106' forming a reel or housing .for the flexible elements. Flange106 is rendered integral to axle 102 by means of set screw 107 and key108; while flange 106' is secured to the same by means of bolts 109, andis provided with a collar portion 108 which fits loosely aroundthe topportion of sleeve 105 and the lower portion of core 116.

For the operation and control of the flexible elements in the mannerwhich will be hereinafter described means are provided for causing theslight axial motion of sleeve 105 necessary to attach or detach the samethrough intimate contact 'with tapered portion 103 of axle 102, or forexerting a braking action on the same. For this, purpose sleeve 105 isformed integral with a flange 119 havin its lower surface inclined downlWardly. round the lower portion of sleeve is mounted a collapsiblecollar formed by two members 137, 137 pivotally mounted on fulcrum pin136' and having their lower internal edge abutting against the lowerinclined surface 119 of flange 119.

The expansion or contraction of said collar is controlled by a screw 141operated by hand wheel 144; and it will be easily understood that ifsaid screw 141 is operated so as to close the collar the action of thesame against t.he.inc1ined surface of flange 119 will be to force sleeve105 in an axial direction out of contact with tapered portion 103, whileif the two c'ollar por-- tions are further drawn together the samt* willexert a brake band action against the lower part of sleeve 105, saidaction being adjustable at will. In the first case, that is, when sleeve105 is detached from tapered portion 103, the sleeve becomes loose onthe axle 102, and may, therefore, rotate independently of said axle,allowing the cables to extend under the action of the centrifugal force.By again opening the 137, 137.', if axle 102 is in a vertical position,sleeve 105 will, by

the action of its ownweight fall back into inerme ing 146 mounted onflange 119. The pres-- sure exerted by said fingers will, therefore,

cause sleeve 105 to move inwardly into contact with tapered portion 103when collar members 137, 137 resume their open position. In order torewind the cables on the reel, handwheel 144 is operated like in theprevious case to close collar members 137, 137'; this will rst causesleeve 105 to become detached from tapered portion 103, and then ashandwheel 144 is further rotated collar members 137, 137 will graduallyexert a braking action against said sleeve causing the same to assume aspeed lower than the speed of axle 1 O2and of reel 106-106 mountedthereon. The four double strand cables held between the reel anges,therefore, which are guided by rollers 50, as shown in Fig. 14, will becaused to wind again around core 116 by the reel itself; since the reel,as stated, rotates at a speed which is higher than the speed of thecore, the core being integral with sleeve 105; the cables will thus begradually retracted and the radius of action of the propeller becomesmaller until through the operation of -handwheel 144 sleeve -105 isagain caused to resume its intimate contact with tapered portion 103. A

From the foregoing it is seen that I have devised a novel method ofconstructing aeroplane propellers having a variable diameter, wherebythe angle of incidence of the elements of which the propeller iscomposed may also be made correspondingly variable; and that by the sameI cause the various factors entering into the operation of a propellerto be automatically regulated so as to make for increased eiiiciency inoperation of the device. It is obvious that once the principle isestablished, many wa s besides the one shown and described may e devisedin order to carry my invention into practlce; and it is thereforeunderstood that I reserve myself the right to modify the details ofconstruction of my invention in such manners as may be suggested byengineering practice in various cases, and as may fairly enter into thescope of the appended claims.

' I claim:

1. In a device of the class described, and in combination with a shaft,a plurality of extensible carriers attached thereto, and wings or planeelements adapted to be' mounted on said carriers, adjustable means formounting said elements on said carriers for controlling their 'angle ofincidence to their plane of travel, the operation of said adjustable!means being controlled by the expansion or retraction of said carriers.

2. In a device of the class described, the combination of a shaft, aplurality of extensible carriers attached thereto, wings or planeelements adapted to be mounted on 4. In a device of the class described,the

combination of a shaft, carriers radially extending therefrom, wings orplane ele-` ments adapted to be mounted on said car riers,v androtatable means for mountin said elements, on said carriers, the axes osaid rotatable means being at right angles to the axes of said carriers.

5. In a device of the class described, the combination of a shaft,carriers radially extending therefrom, wings or plane elements adaptedto be mounted on said carriers, and rotatable means, movabletransversely to said elements, for mounting the same on said carriers.

6. In a device of the class described, the combination with a shaft,carriers radially extendingtherefrom, and wings or lane elements adaptedto be mounted on sai carriers, of rotatable means transversely movablein relation to said plane elements and controlling the angle ofincidence of said elements to their plane of travel.

MARIO SCHIESARI. Witnesses:

- MARIE Zaman, Rose GIsBE'R'r.

